Welcome to the “itch cycle."

Scratching an itch is the most satisfying instant relief available, but according to a new study from Washington University School of Medicine in St. Louis, it’s actually just a mental scam: scratching causes the brain to release serotonin, which intensifies the itch sensation. The more you scratch, the better you feel, and the more you need to scratch the itch.

Scratching, as most of us know, blocks the itching sensation, but doing so can cause pain, which temporarily distracts the brain from the itch. These pain signals are transmitted to the brain by nerve cells, similar to the ones that signaled the itch to begin with.

"The problem is that when the brain gets those pain signals, it responds by producing the neurotransmitter serotonin to help control that pain," said the study’s senior author Zhou-Feng Chen. "But as serotonin spreads from the brain into the spinal cord, we found the chemical can 'jump the tracks,' moving from pain-sensing neurons to nerve cells that influence itch intensity."

So, to recap, you feel an itch based on nerve cells just existing and doing their thing. Then you scratch it, cooperatively, causing relief but also a little pain, which alerts your brain, respectfully, to make the pain stop. Then the resulting serotonin goes completely rogue and basically changes function from stopping pain to just having a good time, signaling that you actually like the itch kind of, and the whole thing starts again.

It’s kind of like asking your roommate to help you clean, but as soon as she starts picking stuff up, she decides she actually likes this whole "clutter is chill" vibe. She’d rather not know where your Apple remote is anyway, because it’s kind of leaving her with a lot more free time, and maybe she’ll just sit here and read a bunch of newspapers and magazines at the same time or eat a huge meal with a lot of bowls instead, just to keep making this worse. Except you can’t sigh angrily at serotonin, you just have to live with it.

Blocking serotonin, however, is not the answer to itch relief, since the chemical is involved in much more important processes of growth, aging, and bone metabolism, is considered a “feel good” hormone. Blocking serotonin would therefore mess with everyday functions, like pain relief, and could have adverse effects on happiness

Instead, Chen and his team went for even more specific territory, working on cells known as GRPR neuron to find that the receptor known as 5HT1A was the key to activating the itch-specific GRPR neurons in the spinal cord.

"We always have wondered why this vicious itch-pain cycle occurs," Chen said. "Our findings suggest that the events happen in this order. First, you scratch, and that causes a sensation of pain. Then you make more serotonin to control the pain. But serotonin does more than only inhibit pain. Our new finding shows that it also makes itch worse by activating GRPR neurons through 5HT1A receptors."

While this information can undoubtedly be used to answer other questions within the body, your best bet for avoiding an itch cycle is still just not scratching. Recommended instant relief that won’t set off tricky brain activity? Unscented lotions, coconut oil, and a gentler soap can all sooth your skin. If chronic itching persists, ask your doctor to check for signs of eczema, or similar skin conditions.